Method of forming a polishing pad having reduced striations

Abstract

The present invention provides a method of forming a chemical mechanical polishing pad, comprising providing a tank with polymeric materials and providing a storage hopper with microspheres having an initial bulk density, wherein the storage hopper further comprises a porous membrane provided over a plenum. The method further provides the steps of connecting a fluidizing gas source to the plenum through a gas inlet line and fluidizing the microspheres and reducing the initial bulk density by feeding gas into the plenum. In addition, the method further provides the steps of providing a delivery system for delivering the polymeric materials and the microspheres to a mixer, forming a mixture of the polymeric materials and the microspheres, pouring the mixture into a mold to form a molded product and cutting the molded product into the polishing pad.

Description

BACKGROUND OF THE INVENTION [0001] The present invention relates to polishing pads for chemical mechanical planarization, and in particular, relates to polishing pads having reduced striations. Further, the present invention relates to apparatuses and methods for forming polishing pads having reduced striations. [0002] In the fabrication of integrated circuits and other electronic devices, multiple layers of conducting, semiconducting and dielectric materials are deposited on or removed from a surface of a semiconductor wafer. Thin layers of conducting, semiconducting, and dielectric materials may be deposited by a number of deposition techniques. Common deposition techniques in modem processing include physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), and electrochemical plating (ECP). [0003] As layers of materials are sequentially deposited and removed, the uppermost surface of the wafer b...

AI Technical Summary

Problems solved by technology

Unfortunately, polishing pads formed in this manner may have unwanted striations.

These striations are unwanted because they may cause unpredictable, and perhaps, detrimental, polishing performances from one polishing pad to the next.

Moreover, these striations may negatively affect polishing performances within the pad itself.

However, prior art apparatuses and methods are inadequate and inefficient at controlling bulk density to meet the ever increasing demands of the CMP industry.

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